[acs-r] ACS: Summing columns but keeping block group geographies

[Ezra Haber Glenn]

Dear Chris:

When called on an acs-class object, the "sum" function sums both rows
and columns, so the geography gets collapsed into a single
"aggregate."   

Alternatively, there is the possibility of using apply() if you only
want to sum rows (MARGIN=1) *or* columns (MARGIN=2).

# to sum all rows *and* all "cols.mf" rows columns:
HSpct.mf <- sum(block.data[,cols.mf])
            
# to sum all columns for each row:

HSpct.mf <- apply(block.data[,cols.mf], MARGIN=2, FUN="sum")

(You could also sum all the rows and keep the columns -- just change
option to MARGIN=1).

Hope that helps -- let me know if you have more questions.

--Ezra

At Mon, 21 Dec 2015 12:09:55 -0800, Chris Cambron wrote:
> 
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> Hi,
> I had a quick question that I can't seem to get a handle on.  I have an ACS object of about
> a 1000 block groups on table B15002 (Sex by Education).  I'm attempting to sum columns
> (i.e. all the columns that indicate not finishing HS for both males and females) prior to
> dividing by the block group total.  However, when I sum columns, I seem to lose my block
> group geography info and all the estimates are aggregated into a single number.  Is there a
> way sum columns to be divided by the total but each geography?
> 
> Any suggestions would be most appreciated.
> 
> vars<-c('B15002001', #Total followed by Males vars then Female vars
>         'B15002002', #Total Male
>        
> 'B15002003','B15002004','B15002005','B15002006','B15002007','B15002008','B15002009','B15002010','B15002011',
> #HS
>        
> 'B15002012','B15002013','B15002014','B15002015','B15002016','B15002017','B15002018', #
> College
>         'B15002019', #Total Female
>        
> 'B15002020','B15002021','B15002022','B15002023','B15002024','B15002025','B15002026','B15002027','B15002028',
> #HS
>        
> 'B15002029','B15002030','B15002031','B15002032','B15002033','B15002034','B15002035') #
> College
> 
> vars<-paste(substr(vars, 1L, 6L), substr(vars, 7L, 9L), sep = '_')
> 
> block.data<-acs.fetch(endyear=2010,span=5,geo=emah.blocks,variable=vars)
> 
> cols.mf<-c(3:11,20:28)
> HSpct.mf <- sum(block.data[,cols.mf])
> 
> Thanks so much,
> Best,
> Chris
> 
> Chris Cambron, MSW, MPP
> Doctoral Student
> Social Development Research Group
> School of Social Work   |  University of Washington
> ccambron at uw.edu  |  www.sdrg.org
> 
> 
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--
Ezra Haber Glenn, AICP
Department of Urban Studies and Planning
Massachusetts Institute of Technology
77 Massachusetts Ave., Room 7-337
Cambridge, MA 02139
eglenn at mit.edu 
http://dusp.mit.edu/faculty/ezra-glenn | http://eglenn.scripts.mit.edu/citystate/
617.253.2024 (w)
617.721.7131 (c)